早教吧作业答案频道 -->数学-->
y=sinx+cosx可化成?A.2sin(x-π/4)；B.2sin(x+π/4)；C.√2sin(x-π/4)；D.√2sin(x+π/4)；
题目详情
y=sinx+cosx可化成_____?A.2sin(x-π/4)；B.2sin(x+π/4)； C.√2sin(x-π/4)；D.√2sin(x+π/4)；
▼优质解答
答案和解析
y=sinx+cosx
=√2*[sinx*(√2/2) +cosx*(√2/2)]
=√2*[sinx*cos(π/4) +cosx*sin(π/4)]
=√2*sin(x +π/4)
=√2*[sinx*(√2/2) +cosx*(√2/2)]
=√2*[sinx*cos(π/4) +cosx*sin(π/4)]
=√2*sin(x +π/4)
看了 y=sinx+cosx可化成...的网友还看了以下：